Enhanced boiling heat transfer using conducting-insulating microcavity surfaces in an electric field: A lattice Boltzmann study

TL;DR

This study uses lattice Boltzmann simulations to show that conducting-insulating microcavity surfaces under electric fields significantly enhance boiling heat transfer by removing the field trap effect and increasing critical heat flux.

Contribution

It introduces a novel microcavity surface design that eliminates the field trap effect and enhances boiling heat transfer under electric fields, supported by a modified correlation equation.

Findings

Critical heat flux increased by over 200% with the new surface.

Electric forces promote bubble departure and prevent vapor block formation.

Pinning effects create multiple vapor-liquid separation paths, boosting heat transfer.

Abstract

The field trap effect on the microcavity surface under the action of an electric field is not conducive to boiling heat transfer. This numerical study found that using conducting-insulating microcavity surfaces in an electric field removes the field trap effect, increasing the critical heat flux by more than 200%. Bubble behavior and heat transfer mechanisms on heating surfaces were further explored. The results show that a large electrical force can be generated at the junction of the conducting and insulating surfaces under the action of the electric field, which drives the bubbles in the cavity to departure quickly from the heating surface and avoids the formation of a vapor block. As the electric field intensity increases, the contact line produces pinning, which facilitates the formation of multiple continuously open vapor-liquid separation paths on the heating surface, resulting in a significant enhancement of the boiling heat transfer performance. Finally, a modified correlation equation is proposed to predict the critical heat flux under non-uniform electric field.